The prior art is already aware of many different arrangements for connecting pistons to piston rods and for attaching cylinder heads and glands or the like to the end of a cylinder. These arrangements include contsructions which do not utilize threaded inter-connections, such as threading a piston rod into a piston or a cylinder head into the end of a cylinder. That is, the arrangements already known and used for attaching pistons to rods and attaching cylinder heads to cylinders commonly include threaded members and members which require close tolerances and several parts for achieving the attachments. In those prior art arrangements, the cylinder assemblies are expensive to manufacture and to repair, but they do not necessarily produce a more efficiently operating assembly. Also, special tools are frequently required for assembling and repairing the prior art assemblies.
In the present invention, the attachment of the piston to the rod and of the cylinder head to the cylinder is accomplished without the use of threaded means or other fasteners or other types of connections, including welding, all of which bear axial force transmitted between the aforesaid connected parts. Prior art examples of the utilization of and therefore the requirement for relying upon threaded means or other types of connections for resisting axial forces between the connected parts are found in British Pat. No. 718583 and U.S. Pat. Nos. 748233 and 970903 and 1,521,388 and 1,538,132 and 2,729,523 and 3,108,514 and 3,115,071 and 3,168,301.
The prior art is also aware of connections between a piston and a piston rod utilizing a groove in the rod and a split ring nested in the groove and somehow held relative to the piston. Examples of such prior art are found in U.S. Pat. Nos. 3,055,719 and 3,397,893 and 3,426,656 and 3,426,657 and 3,457,842 and 4,004,499. Of these patents, the first two have the split ring extending to the outer circumference of the piston itself and the piston is therefore necessarily made in two halves and a number of additional parts. The multiple piece piston arrangement is also shown in the last two patents listed above, and, in all of this list, the showings are limited to having a separate split ring for each single groove in the piston rod. As such, either special arrangements are made for entraping the split ring relative to the rod or for bearing down axially on the split ring for firmly holding it axially of the rod. Thus, U.S. Pat. Nos. 3,426,656 and 3,426,657 require a threaded member in the form of a slip-fit locking nut which axially bears against the single split ring. Also distinguishable over the invention herein is the showing in U.S. Pat. No. 3,457,842 which has a split ring held by a required bearing band, both of which extend to the cylinder wall itself and must therefore be fitted relative to the wall for sliding thereon. Finally, U.S. Pat. No. 4,004,499 shows an arrangement of a single rod groove and a single tongue or split ring nested in the groove and a fitted end ring 12 is shown and is part of the piston itself, all for holding the split ring in position on the rod.
The present invention employs the split ring principle wherein there is a plurality of projections or tongues and grooves within one split ring, and no threaded member or fitted band or the like is required to hold the split ring radially inwardly against its connecting part, such as the piston rod or the cylinder head. Therefore, an inexpensive but sturdy and reliable connection is possible between the piston and the rod and between the cylinder head and the cylinder, and the split ring may be employed at either or both those locations.
The further object of this invention is to provide either or both of the aforesaid connections by utilizing a split ring at the location where a threaded member has been commonly heretofore utilized. That is, the split ring can replace a threaded connection between the rod and the piston, or on the end of the rod to hold the piston against a shoulder on the rod, and it can be used to replace the threaded connection between the cylinder head and the cylinder itself. As such, there is improved serviceability and reduced cost and the connection can actually be sturdier than that provided by conventional threading.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.